doar ce știți ..
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2.
b=400 lei
a) 400x10%=400x10/100=4000:100=40
400+40=440 pret dupa prima marire
b) 440x10%=440x10/100=4400:100=44
440+44=484 dupa a doua marire
c) 484-400=84
84x100:400=8400:400=21%